Prosecutions for re-entering the country illegally account for about one-third of all federal cases in Los Angeles and surrounding counties, the Los Angeles Times reported Sunday.

The newspaper said there were 539 such cases in fiscal year 2007, which was 35 percent of the U.S. attorneys' caseload, compared with 207 cases in 2006, or 17 percent of all cases. Statistics for the first four months of this fiscal year show the trend continuing, the Times reported.

Authorities said they were targeting gang members, drug dealers and career criminals, the newspaper said. Authorities also are combing U.S. jails and prisons for illegal immigrants.

"They are some of the worst of the worst," Julie Myers, assistant secretary of Immigration and Customs Enforcement, told the newspaper. "They are people that citizens of any community would want off the streets."

Critics, including Bruce Einhorn, a former immigration court judge, said federal prosecutors should spend more resources going after smugglers.

"That would do more to stop dangerous illegal immigration than by prosecuting a few more undocumented people who have re-entered illegally," he said.